My pattern is for a baby sweater that is knitted in one piece from the neckline down. I reached a step where I had to divide for the sleeves and the body. As I worked on the instructions for the sleeve, I was instructed to work back and forth in my pattern increasing stitches on the edges until the length of the sleeve from the point of division reached 4 1/2 inches. Should the 4 1/2 inches be measured along the diagonal (an increasing edge) from the point of division or straight down from the point of division?